This invention relates to a method for the production of hydrogen by thermochemical decomposition of water. More particularly, the present invention relates to a method for the production of hydrogen by thermochemical decomposition of water by use of tri-iron tetraoxide and hydrogen bromide as the main cyclic reaction media.
Hydrogen is attracting ever increasing attention not only for its widespread utility in industrial applications but also for its potential as an energy source promising to replace fossil fuels as the secondary source of energy after the depletion of the latter. The development of so-called hydrogen energy systems has been enthusiastically pursued in recent years through research denoted to producing technology for the production, storage and utility of hydrogen.
Recently, there has been proposed a thermochemical method, i.e. a method for decomposing water into hydrogen and oxygen by effective use of a plurality of chemical reactions caused by the high-temperature thermal energy generating from high-temperature gas reactor, for example. Great attention is now being focused on this method, for it is expected to offer higher thermal efficiency than the water electrolysis. For the thermochemical production of hydrogen, a number of methods involving use of varying cyclic reaction media have already been proposed.
One of these methods has been proposed by the present inventors (U.S. Pat. No. 3,996,342): This method accomplishes the production of hydrogen by the thermochemical decomposition of water by use of barium iodide, carbon dioxide and ammonia as cyclic reaction media.
Recently, the iron-chlorine cycle in which iron and chlorine are used as cyclic reaction media is attracting keen attention.
Many reaction cycles have been proposed for the thermochemical production of hydrogen by the iron-chlorine cycle. Of the many cycles proposed, the following three are representative: